Professor Gellene is supported by a grant from the Experimental Physical Chemistry Program to use absorption and emission spectroscopy to study the neutral radicals which are in the neighborhood of the transition state on the potential energy surface of a polyatomic molecule. The neutral radicals are produced by reneutralization of an ion beam and either remain in the transition state long enough to be observed in absorption spectroscopy or are in excited Rydberg states which vertically radiate to transition state regions by emission. Probing the transition state directly is important because the characteristics of the transition state region largely determine reactive events. This approach is potentially applicable to systems for which the geometry of the positive ion closely resembles that of the transition state region. Specifically the technique will be applied to a study of 3- and 4-atom radicals containing H(or D), N, O and F. %%% By preparing a species that has a structure that is in between the reactants and the products and doing spectroscopy on it in the relatively short time that it exists in this geometry, Professor Gellene hopes to characterize that state, called the transition state, which largely determines how a chemical reaction proceeds.
